Lesson 4: Fuel Costs and Fuel Economy Fuel Economy (Fuel Consumption) A major operating cost of a vehicle is the gasoline. Different vehicles require different amounts of gasoline to drive the same distance. The number of litres of gasoline a vehicle requires to travel 100 km is known as its fuel economy rate. The fuel economy rate of your vehicle affects your gasoline costs. A higher fuel economy rate corresponds to a higher cost of driving your vehicle a certain distance (and a lower rate costs lower costs). For example, a fuel economy rate of 7.4L/100 km means that 7.4 litres of gasoline are required to travel 100 km. The fuel economy rate of your vehicle will vary depending on: When you drive How you drive The type of vehicle you drive The types of optional equipment installed The condition of your vehicle Most manufacturers voluntarily place a fuel economy rate label on new vehicles. The labels state the city and highway fuel economy rates for that particular model. The fuel economy rate is higher for city driving than highway driving because of stop-and-go driving. Extra fuel is used while a vehicle is idling during a red light, and while accelerating. (*Note: when bought new, it could take up to 10 000 km for the vehicle to reach the stated fuel economy rate) Page 1 of 8
The following is the formula for determining the fuel economy of a vehicle: Fuel economy rate = litres of gasoline required x 100 Kilometres driven Fuel economy rate is expressed in L/100 km. NOTE: *This is on the provincial exam formula sheet: FOR YOUR INFORMATION ONLY (NOT TESTABLE): In the US, fuel economy is measure in miles per gallon, and many Canadians still use the term gas mileage to describe fuel economy as miles per (imperial) gallon instead of litres per 100 km. To convert, divide 282.5 by one system to get the other. As examples: Ex 1) 282.5 / (25 mi/gal) = 11.3 L/100 km *imperial gallon Ex 2) 282.5 / (8.5 L/100 km) = 33.2 mil/gal Also, the US gallon has a different conversion factor of 235. Page 2 of 8
Example 1: At 60 km per hour, a sedan uses 18.4 L of gasoline to drive 225 km. At 100 km per hour, the sedan uses 22.1 L of gasoline to drive the same distance. a) Find the fuel economy rate for the sedan at 60 km/hr. b) Find the fuel economy rate for the sedan at 100 km/hr. c) Find the percent increase in fuel economy. Solution: a) Fuel economy rate = litres of gasoline required x 100 kilometres driven = 18.4/225 x 100 = 8.2 (rounded to the nearest tenth) The fuel economy rate at 60 km/hr is 8.2 L/100km. b) Fuel economy rate = litres of gasoline required x 100 kilometres driven = 22.1/225 x 100 = 9.8 (rounded to the nearest tenth) The fuel economy rate at 100 km/hr is 9.8 L/100km. c) The increase in fuel economy rate = 9.8 8.2 = 1.6 L/100km. You need to find the percent increase in fuel economy. To do this, you need to divide the increase in fuel economy by the lower fuel economy, than multiply by 100. Percent increase in fuel economy = 1.6/8.2 x 100 = 19.5 % The rate of percent increase is 19.5%. The fuel economy rate of a vehicle can be used to calculate the number of litres of gasoline required to drive a specified distance. The number of litres of gasoline required by a vehicle to drive a given distance = fuel economy rate of the vehicle x distance 100 Page 3 of 8
Example 2: The Fender family is planning a vacation where they will drive a distance of about 5000 km. The family has two vehicles: a sedan and a van. The fuel economy rate is 8.8 L/100km for the sedan and 12.7 L/100km for the van. a) Calculate the amount of gasoline required by the sedan to complete the trip. b) Calculate the amount of gasoline required by the van to complete the trip. c) Which vehicle would be more fuel efficient and, therefore, less costly to drive? d) What other factors might the Fender family consider as they decide which vehicle to take on their vacation? Solution: a) The number of litres of gasoline required by the sedan = fuel economy rate of the vehicle x distance 100 = 8.8 / 100 x 5000 = 440 L of gasoline b) The number of litres of gasoline required by the van = fuel economy rate of the vehicle x distance 100 = 12.7 / 100 x 5000 = 635 L of gasoline c) The sedan is more fuel efficient and less costly to drive since it requires 195 L less of gasoline to complete the trip. d) Other factors the Fender family might consider are the age, condition, and comfort of the vehicles. Page 4 of 8
Fuel Costs Fuel costs vary across North America. Fuel costs can even vary within the city. COST (in $) = Litres of Gas X Cost of Gas per Litre (in dollars) Understand these three calculations: Example 3: How much does it cost to fill a 40L tank at $1.21/L? Example 4: What is the cost per litre if a 50L tank costs $58 to fill? Example 5: How many litres does it take to fill a tank that costs $60 to fill at a price of $1.10 / L? Example 6: The odometer of a mid-size car reads 34 719 at the beginning of a trip and 34 853 at the end. The car consumes 12.4 L of gasoline during the trip. Recall that the odometer of a car tells you the total distance (in km) the vehicle has been driven during its entire life. a) Determine the fuel economy of the sedan. b) If the cost of gasoline is 112.94 per litre, find the cost of driving 100 km. Solution: a) The number of km driven during the trip = 34 853 34719 = 134 km Fuel economy rate = 12.4 / 134 x 100 = 9.3 L/100km. b) The cost of gasoline = 9.3 x 112.9 = 9.3 x $1.129 = $10.50. Page 5 of 8
Assignment 4 1. Complete the following chart. a) b) c) d) e) f) g) h) Litres Cost/Litre Total Cost 90 $1.05 18 $1.20 51.3 95 cents 58.2 $65.06 82.7 $79.10 $1.08 $45.60 $1.13 $53.80 98 cents $49.21 2. Distance Driven **The odometer on your car shows how far you have travelled. Distance Travelled = Final Distance Initial Distance a) Initial = 039287.6 Final = 040324.3 distance travelled = b) Initial = 076543.2 Final = 076956.7 distance travelled = Page 6 of 8
3. A car requires 52 liters of gasoline. If the cost of gasoline is $1.20 per liter, calculate the cost to fill the tank. 4. A bill for gasoline was $21.50. If the cost of gas is $1.41 / liter, determine the number of liters purchased. 5. A car consumed 70 liters of gasoline which cost $89.25. What was the cost per liter? 6. Jannie takes her sedan for a drive through the city. At the beginning of her trip, the odometer reads 114 570; at the end of her trip, the odometer reads 114 637. a) How far did Jannie drive? b) If Jannie used 16.3 L of gasoline, what is the fuel economy rate of her vehicle? c) Would the highway fuel economy rate be higher or lower than the rate you found in part (b)? Explain. Page 7 of 8
7. Brigette travelled in her minivan to Churchill to watch the polar bears and kept track of her gas purchases. For each part of the trip, she would like to know: (i) km driven, (ii) cost of each fill-up and (iii) fuel economy in L/100km. She left with a full tank of gas and an odometer reading of 51 372.0 Final Reading KM driven since last fill liters Cost / Liter Cost of fill up 51 570 198 km 27.2 $1.12 $30.46 Fuel Economy in L / 100 km 13.7 L/100km 51727 27.2 $1.13 51 947 41.8 $1.08 Example work: i) Km Driven = 51 570 51 372 = 198 km ii) Cost of fill up = 27.2 x 1.12 = $30.46 iii) Fuel Economy (L/100km) = 27.2 x 100 = 13.7 L/100km 198 8. Using the info from the chart in Ques # 7, answer the following questions: a) What was the total quantity of gas purchased? b) What was the total cost? c) What was the average fuel economy for the whole trip? Page 8 of 8